Various measuring events are involved in the process industry. In certain sectors, however, the measuring events can be technically challenging situations. An example of process industry sectors wherein special specifications are set for measuring devices used in liquid measurement, for instance, in the semiconductor industry. In the semiconductor industry, liquids used in the process can be highly corrosive acids or bases. Examples thereof include KOH, hydrogen peroxide, and hydrogen fluoride (HF).
The character of the process of the semiconductor industry, metals can be forbidden materials in parts that come into contact with the process. A small amount of metal ions can contaminate the end products of the process, for example, microcircuits. Consequently, as the structural materials for process measuring devices and actuators, the semiconductor industry uses plastics and minerals. Examples of the materials used include fluoroplastics (PTFE, PVDF, PFA, ECTFE) and synthetic gemstones, such as Spinel, YAG, GGG, and sapphire.
Fluoroplastics can be used for structural materials for pipe system parts in the semiconductor industry, since they can be relatively easy to work with, are light and relatively reasonably priced. However, the physical properties of the plastics can be limited, and in connection with optical tasks or tasks using heat conduction, such that synthetic gemstones or minerals are used instead.
The optical properties and wearing properties of non-metal, synthetic gemstones can be excellent, and heat conductivity, for instance, is in the same order as that of metal materials. Ceramic materials, too, have similar properties, so these non-metal materials can also be usable in some embodiments.
On the basis of the foregoing, the aforementioned materials can be suitable for use as structural materials in the semiconductor industry in demanding tasks.
An issue with the known art is the fastening of parts manufactured from the aforementioned materials, for example, synthetic gemstone, and parts manufactured from a plastic material. In measuring sensors used in the semiconductor industry, for instance, the part contacting with the process medium can be manufactured from a synthetic gemstone material while the rest of the mechanics is made of plastic.
In the above-described situation, it can be difficult to find a way of connection that would be optimal in every respect. Screw and thread connections are seldom used because of the hardness of synthetic gemstones. Press and fitting connections may not be possible because of the poor mechanical properties of plastics.
For example, a window or a measuring sensor manufactured from a synthetic gemstone can be subjected to forces caused by the process, such as flow and pressure, as well as forces caused by using the device, such as torsion, tension, and compression. Synthetic gemstones can also be more difficult and more expensive to work than plastics and metals, so the mechanical shapes of parts manufactured from a synthetic gemstone can be relatively simple.